[ubernostrum]

From what I read of the Digg article, it seemed they were hitting situations where doing some work in PHP rather than the DB was the most efficient solution. I don't find anything unreasonable about that; I occasionally run into situations where it's just not possible to get the performance needed while only using the DB, as does probably anyone who's worked enough with databases.

The specific case -- IIRC -- Digg mentioned was a query which required MySQL to generate a temporary table too large to sit in memory, so it ended up being done on disk. Moving some of the processing out of the DB query and into PHP avoided that, understandably resulting in a huge performance difference (in-memory versus on-disk has a way of doing that...).